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Making ZFS and DTrace Work On Ubuntu Linux
New submitter Liberum Vir writes "Many of the people that I talk with who use Solaris-like systems mention ZFS and DTrace as the reasons they simply cannot move to Linux. So, I set out to discover how to make these two technologies work on the latest LTS release of Ubuntu. It turned out to be much easier than I expected. The ports of these technologies have come a long way. If you or someone you know is addicted to a Solaris-like system because of ZFS and DTrace, please, inquire within."
So what am I supposed to do about all the kernel panics and absurdly slow IO and transfer speeds?
So there's a list of 10 steps to install zfs and that's it? Didn't do anything? zfs/zpool upgrade -v? zvols? zfs send/receive? snapshots? rollback? Scrub? Performance tests? Compression? Encryption? Can I export my pool from my Solaris 11 SPARC system and import it into linux, make some changes and then move it? L2ARC support? Separate ZIL support? Case sensitivity?
I know this isn't exactly a great comment, but is it at all possible that someone make a judgement as to the value and truth of a submission before putting it up?
The whole GPL/CDDL issue is still around, however, since the CDDL code is not added to the Linux Kernel, but instead a loadable kernel module distributed separately, it is possible to satisfy both the GPL of the Linux Kernel and the CDDL of ZFS and DTrace. Because of the incompatibility of CDDL with the GPL, you could not distribute a complete system using of Linux, ZFS, and DTrace. You can, however, distribute packages to allow people to build it themselves. This is what the authors of these projects have done.
I just looked at this article as my employer uses Debian and Ubuntu heavily and I've been pushing for ZFS on our file servers. There is no mention of ZFS version, the feature set available, or even a link to the source material.
ZoL is based on ZFS version 28 from the last open Solaris release, and currently integrating Illumos as its upstream.
There isn't much mention of how to use ZFS. I happen to know most commands, but I think this article would be difficult for a beginner even though it seems to be targeted at that demographic.
It looks like the Slashdot editors are doing this blogger a favor by linking to a mostly empty article.
At a minimum, this article should link to the ZoL home page, the ZoL Launchpad page for packages, and maybe the ZFS introduction or another tutorial.
I've been running ZFS on FreeBSD for a few years and it's lived up to its promises, but I think I'll be migrating off of it. The problem is that I trusted Sun. They did some goofy things, but you knew where you stood with them. They release ZFS under an Open Source license? You could take them at face value and know that you were allowed to use it. But now that Oracle holds the reins, I have no desire to depend on any Sun-borne projects anymore. Yes, ZFS is Open Source. So was Java, and Google just spent roughly a bazillion dollars defending themselves for using something that looked like it. I can't afford to take on a case like that.
Other than the Oracle-owned btrfs, what ZFS alternatives are available and ready for use today?
Dewey, what part of this looks like authorities should be involved?
I always thought the hold up on ZFS and DTrace on linux was the fact the CDDL and GPL didn't play nicely with each other. It was never a technical reason.
I've been running both on FreeBSD for a couple years now. Still don't have any production machines with ZFS yet, but I've found DTrace to be a life saver on more than a few occations.
"The problem with socialism is eventually you run out of other people's money" - Thatcher.
I use ZFS on Ubuntu 11.10 in "production" for my main workstation and fileserver with a 3x3TB raidz pool with an L2 ARC. I/O is blindingly fast, and it has been rock solid. It serves about 10 machines, and feels an order of magnitude faster than the md/lvm based xfs array it replaced.
I write 10GbE drivers for Linux, MacOSX, FreeBSD and Solaris. I make heavy use of Dtrace for both debugging and performance analysis. I feel naked without Dtrace, and I've used the linux dtrace a few times for debugging. Unfortunately, I've never had dtrace run on linux for more than a few minutes without crashing a machine. This is not necessarily bad, and often just a few seconds is all I need. But I would never run linux Dtrace on any production machine, whereas I use it all the time under Solaris / FreeBSD and MacOSX and often have customers run Dtrace probes on those OSes to diagnose issues.
So an article lacking knowledge of the technologies, any sort of testing, anything beyond "make install" or "apt-get install", will make it to the Slashdot homepage? This person openly admits that they didn't test ZFS beyond creating a zpool, and they don't know enough about DTrace to try... anything.
As an aside, why was Linux capitalized, but Solaris was not?
- oZ
// i am here.
The DTrace integration is via a kernel module, so the license on DTrace is irrelevant..
There are a couple of interfaces in Linux that should be externalized for getting stack tracebacks into user space in a standard manner without caring about binary architecture (they are currently static). I've personally used a modified Linux with DTrace mods and these functions externalized, and it's rather stable and usable. Specultive tracing is also a lot better for finding the origin of some random errno in the kernel, or who in user space is calling gettimeofday() a bazillion times in order to time stamp X events.
Obligatory disclosure: I was on the team that did the DTrace port to Mac OS X.
-- Terry
OpenIndiana has only made three "development releases" since 2010, it is not a production grade system. Just a hobbyist system.
Congrats... this is a good summary on getting these working under Ubuntu. I did the ZFS install "naked" (without a summary as good as this) with a 10.04 box about a year ago and it has run great guns. Now, having said that it's good for what I use it for which is a temporary location to dump my SQL backups to from a large email archive using dedupe prior to running it off to tape... and another zpool mounted as an archive VMFS volume through NFS to our VMware farm so we can archive decommissioned virtual machines for 30 days prior to deletion per our policy. I am not 100% convinced I would use it for anything production though; supportability is still an issue with this and as such I remain a little dubious whereas with most of our system I can call a vendor and have them fix it. As the storage admin I find this a great way to keep up with the demands for storage while having a relatively transparent way (for my admins) to put stuff into a place where it doesn't take up so much space.
Now having said that there are some caveats; as the zpool gets really large the ability to delete files becomes slower and slower when it's deduped. This is because a lot of database transactions take place to remove the files particularly when there's a lot of deduplicated blocks... and this problem is a lot worse under Ubuntu than it was under OpenSolaris (which is where I first played with ZFS). There are times also that when reading the SQL backups to dump them to tape it can make both storage pools unresponsive enough that VMware drops the NFS datastore and I have to manually remount them. Far less than perfect... but good enough for what we use it for.
I have recently taken a decommissioned physical server (a DL380 G5 with two processors and 16GB of RAM) and put OpenIndiana on it to play with ZFS some more and it is working fantastically well. In my tests though it still has the slowdown issues, high utilization in one pool won't cause the other pool to grind to a halt when both are deduped. Also, it's been nice to (at least in test) create a ZVOL on my ZFS and present it through fiber-channel to my VMware hosts as a potential replacement for the NFS volume on Linux (I have only Emulex cards, and I have yet to see a properly working Emulex target mode under Linux). So far my testing has gone marvelously and I have found dedupe rates to be about the same as the NFS mounted volume... though slightly lower. I suspect that's probably because the data isn't really block aligned all that well but it still saves me a bunch of storage when we have 30 almost identical virtual machines being archived! On the bright side there I have not yet seen utilization get so high on the OI box that it causes any significant issues or dropouts that cause VMware to complain; so far it's been rock solid. I may migrate my ZFS stuff to the OI box and get it off my Ubuntu box... but at the moment they're both working great and I have no complaints.